Recording device utilizing inter-symbol interference

ABSTRACT

A recording device according to the present invention has a function (202, 206, 207) of dividing precoded record data into data blocks of a prescribed length to adjust to a magneto-optical disk (3) and adding an intrinsic pattern before and after the data blocks. As the intrinsic pattern, a pattern which reduces a decoding error of maximum likelihood decoding at an end of each data block is used. Therefore, even when data is inserted after preceding, code correlation of a precoded signal can be maintained at a location where division is performed.

TECHNICAL FIELD

The present invention relates to a recording device for recording dataon a magneto-optical recording medium.

BACKGROUND ART

A magneto-optical recording and reproducing system can be regarded as aGaussian low pass filter if the entire part is considered to be a baseband transmission line. Therefore, an increase in the recording densitycauses inter-symbol interference between the minimum signals of adjacentrecording regions and thus deteriorates a regenerated signal waveform.

As one of the methods of preventing such inter-symbol interference, themethod of correcting the frequency characteristic of the entiretransmission line to a Nyquist characteristic by providing an equalizerat a later stage of a magneto-optical recording and reproducing systemis known. However, since the transmission band is limited in thismethod, it is difficult to apply the method to recording and reproducingof a high density magneto-optical disk.

Therefore, the PR (Partial Response) method in which inter-symbolinterference is not eliminated but a signal is transmitted withinter-symbol interference is employed for recording and reproducing of ahigh density magneto-optical disk.

A transmission system in which the PR method is applied to amagneto-optical disk will be described with reference to FIG. 9.Referring to FIG. 9, a precoder 701, a magneto-optical disk 704 in whicha signal is recorded and regenerated by an optical pickup 702 and amagnetic head 703, and an equalizer 705 form the transmission system.Precoder 701 eliminates error propagation caused when a code that istransmitted by the PR method is decoded. Equalizer 705 performs waveformequalization of an RF signal regenerated from magneto-optical disk 704.That results in inter-symbol interference having known correlation asthe transmission system.

Multi-value discrimination portion 706 estimates the most possible stateof a signal by maximum likelihood decoding. More specifically, theamplitude correlation of the PR method is utilized to refer to the stateof a decoded signal before time for identification (or before and afteridentification time) and to estimate the most analytically possiblevalue to be the signal state at the identification time.

In signal transmission of the PR method, it is desirable in some casesto divide a precoded signal (signal after being precoded) into blocks ofa prescribed bit number and to insert an intrinsic pattern or the likeof the drive system before and after each block. For example,magneto-optical disk 704 may be caused to have a clock component inadvance and data may be recorded on locations other than that of theclock component.

If data is inserted after precoding, however, the code correlation of aprecoded signal cannot be maintained at a location where division intoblocks is found. Then, a decoding error occurs in maximum likelihooddecoding which utilizes signal correlation before and afteridentification time.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a recording devicecapable of inserting data in a precoded signal without causing adecoding error of data.

According to one aspect of the present invention, a recording device forrecording data on a recording medium of a method in which data isreproduced by utilizing inter-symbol interference includes precode meansfor precoding input data to adjust to the recording medium, format meansfor dividing the precoded data into a plurality of data blocks andadding a corresponding intrinsic pattern to an end of each of theplurality of data blocks, pattern determination means for determiningthe corresponding intrinsic pattern for each of the plurality of datablocks and outputting the corresponding intrinsic pattern to the formatmeans, and record means for recording an output of the format means onthe recording medium, wherein the pattern determination means determinesthe corresponding intrinsic pattern to reduce a decoding error of dataat each end of the plurality of data blocks. Preferably, the patterndetermination means selects one of predetermined at least two intrinsicpatterns as the corresponding intrinsic pattern for each of theplurality of data blocks. Preferably, the corresponding intrinsicpattern is formed of such data among data included in a data blockadjacent to a corresponding data block that is adjacent to an end of thecorresponding data block before division into blocks.

Therefore, according to the above described recording device, even whenan intrinsic pattern is inserted and recorded for precoded data and therecorded data is read out and subjected to waveform equalization toperform maximum likelihood decoding, code correlation at a locationwhere division into blocks is performed can be maintained. It istherefore possible to prevent occurrence of the decoding error ofmaximum likelihood decoding at the block division location.

According to another aspect of the present invention, a recording devicefor recording data on a recording medium of a method in which data isreproduced by utilizing inter-symbol interference includes precode meansfor precoding input data to adjust to the recording medium, format meansfor dividing the precoded data into a plurality of data blocks andadding a corresponding first intrinsic pattern to a front end of each ofthe plurality of data blocks and a corresponding second intrinsicpattern to a rear end of each of the plurality of data blocks, patterndetermination means for determining the corresponding first intrinsicpattern and the corresponding second intrinsic pattern for each of theplurality of data blocks, and record means for recording an output ofthe format means on the recording medium, wherein the patterndetermination means determines the corresponding first intrinsic patternaccording to the rearmost data of a data block located immediatelybefore a corresponding data block, and determines the correspondingsecond intrinsic pattern according to the rearmost data of thecorresponding data block. Preferably, the corresponding second intrinsicpattern is combined with the rearmost data of the corresponding datablock to generate traceback. Preferably, the rearmost data of thecorresponding first intrinsic pattern is identical to the rearmost dataof the data block located immediately before the corresponding datablock.

Therefore, according to the above described recording device, even whenan intrinsic pattern is inserted and recorded for precoded data and therecorded data is read out and subjected to waveform equalization toperform maximum likelihood decoding, code correlation at a locationwhere division into blocks is performed can be maintained. It istherefore possible to prevent occurrence of the decoding error ofmaximum likelihood decoding at the block division location. When anintrinsic pattern which generates traceback is inserted, maximumlikelihood decoding can be completed for each data block.

The foregoing and other objects, features and advantages of the presentinvention will become apparent from the following details of the presentinvention understood in conjunction with the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram illustrating an overall configuration ofa recording/reproducing device according to a first embodiment.

FIG. 2 is a conceptual diagram showing one example of the configurationof a modulation portion 2.

FIG. 3 is a conceptual diagram showing a data format of a user data areain the first embodiment.

FIG. 4 is a block diagram showing one example of the configuration of ademodulation portion 6.

FIGS. 5A and 5B show tables referred to during data formatting in thefirst embodiment.

FIG. 6 is a conceptual diagram illustrating the structure of amagneto-optical disk 3.

FIG. 7 is a conceptual diagram showing a data format in a secondembodiment.

FIGS. 8A and 8B show tables referred to during data formatting in athird embodiment.

FIG. 9 is a conceptual diagram illustrating a transmission systemcorresponding to a conventional PR method.

BEST MODES FOR CARRYING OUT THE INVENTION First Embodiment

Referring to FIG. 1, a recording/reproducing device according to a firstembodiment includes a recording system 10 including an error correctingcode portion 1 and a modulation portion 2, an optical pickup 4 and amagnetic head 5 arranged for a magneto-optical disk 3, and a reproducingsystem 20 including a demodulation portion 6 and an error correctingdecode portion 7.

Error correcting code portion 1 adds an error correcting code toreceived user data. An output of error correcting code portion 1 isdigitally modulated in modulation portion 2. The digitally modulateddata is recorded on magneto-optical disk 3 by optical pickup 4 andmagnetic head 5.

The record data recorded on magneto-optical disk 3 is read out byoptical pickup 4, and digitally demodulated in demodulation portion 6.The digitally demodulated data is error-corrected in error correctingdecode portion 7 and provided as an output.

As shown in FIG. 2, modulation portion 2 includes modulation units U0 toU15, a discrimination portion 205 for discriminating data having thesmallest amount of DC component by comparing the DSVs (digital sumvalues) of data modulated by modulation units U0 to U15, a selectionportion 204 for selecting digitally modulated data output from one ofmodulation units U0 to U15 based on the discrimination result ofdiscrimination portion 205, a formatter 206 for adding a patternintrinsic to the recording/reproducing device to the selected data, anda prediction portion 207 for controlling formatter 206 based on theselected data.

Each of modulation units U0 to U15 includes a scrambler 201, a precoder202 and a DSV calculation portion 203. Scrambers 201 use mutuallydifferent scramble keys to scramble data and add the scramble keys todata. Precoders 202 precode the scrambled data to prevent errorpropagation. DSV calculation portions 203 calculate the DSVs of theprecoded data.

Data output from error correcting code portion 1 is converted to 16types of precode data in modulation units U0 to U15. Discriminationportion 205 receives outputs of respective DSV calculation portions 203in modulation units U0 to U15 and performs the above describeddiscrimination. In selection portion 204, precode data having thesmallest amount of DC component is selected among the 16 types ofprecode data. Formatter 206 divides the selected data into data blocks(the operation is referred to as block division), and adds an intrinsicpattern determined by prediction portion 207 to each data block.

The storage area of magneto-optical disk 3 is formed of a user data areafor recording user data, and a system data area for recording dataintrinsic to the recording/reproducing device. Input user data isdivided into data blocks of 512 DCB (data channel bit) units informatter 206 as shown in FIG. 3. Data forming each data block isreferred to as Data D (0) to D (511).

A pre-write field, a post-write field and an FCM (Fine Clock Mark) fieldare added before and after the data block. The pre-write field and thepost-write field both have 4 DCB units, and the FCM field has 12 DCBunits.

A data block, a pre-write field, a post-write field and an FMC fieldconstitute a data segment. In FIG. 3, data segments N to N+3 arerepresentatively shown. In the following, a data block forming a datasegment K (K is an integer of at least 0) is referred to as a data blockK.

On tracks of magneto-optical disk 3, marks for clock generation (FCMs:fine Clock Marks) are previously formed as physical forms. An FCM fieldcorresponds to an area where the FCM is formed. In a pre-write field anda post-write field, fixed patterns described below are recorded as databased on an indication from prediction portion 207. It is noted that thepre-write field and the post-write field are arranged for buffering sothat part of the data block (front or rear portion) does not enter anFCM when the recording position of the data block is slightly shiftedfrom that of ordinary cases. In other words, the pre-write field and thepost-write field function as buffering data to connect the FCM and data.The user data formatted in this manner is recorded on magneto-opticaldisk 3.

As shown in FIG. 4, demodulation portion 6 shown in FIG. 1 includes anA/D converter 601 for digitally converting an RF signal regenerated byoptical pickup 4, an equalizer 602 for performing waveform equalizationof the regenerated RF signal to attain a desired characteristic, amulti-value discrimination portion 603 for performing maximum likelihooddecoding to demodulate binary data according to the amplitude level ofan output of equalizer 602, an unformatter 604 for extracting user data,and a descramber 605 for descrambling the extracted user data based onscramble header information.

Now, formatting by prediction portion 207 and formatter 206 in the firstembodiment will be described with respect to data blocks N and N+1, asan example. In the first embodiment, an intrinsic pattern determined bythe last data D (511) included in data block N of data segment N isinserted in a pre-write field corresponding to data block N+1 (datasegment N+1). In a post-write field corresponding to data block N (datasegment N), an intrinsic pattern determined by the first data D (0)included in data block N+1 of data segment N+1 is inserted.

More specifically, as shown in the tables (conversion rule) of FIGS. 5Aand 5B, if intrinsic patterns corresponding to a pre-write field are“1100” and “0011” and the last data D (511) in data block N is “0,” then“1100” is inserted in the pre-write field corresponding to data blockN+1. If the last data D (511) is “1,” then “0011” is inserted in thepre-write field corresponding to data block N+1.

If intrinsic patterns corresponding to a post-write field are “0011” and“1100” and the first data D (0) in data block N+1 is “0,” then “0011” isinserted in the post-write field corresponding to data block N. If thefirst data D (0) is “1,” then “1100” is inserted in the post-write fieldcorresponding to data block N.

Prediction portion 207 refers to the tables (conversion rule) of FIGS.5A and 5B to determine an intrinsic pattern. Formatter 206 inserts,based on an indication from prediction portion 207, an intrinsic patternin a pre-write field and a post-write field before and after a datablock.

By thus inserting, into a portion (a block division location) before andafter block data obtained by block division, an intrinsic patterndetermined by data at an end of an adjacent data block, code correlationat block division location D (0) and D (511) is maintained.

Therefore, without causing a decoding error in maximum likelihooddecoding in multi-value discrimination portion 603, it becomes possibleto insert particular intrinsic patterns in precoded data.

Besides the above described data format, the present invention iseffective for a stream having such a data format that precoded data isdivided into data blocks of a prescribed length and a particular patternis inserted in each data block.

It is noted that an intrinsic pattern may be inserted not only beforeand after a data block but before or after the data block according tothe above described conversion rule.

Second Embodiment

A data format in a second embodiment will be described. Inmagneto-optical disk 3, grooves (trenches) shown in FIG. 6 are formed ina spiral manner. In a groove, convex portions 55 are formed atprescribed intervals. In a land located between adjacent grooves,concave portions 50 are formed at prescribed intervals. Concave portions50 and convex portions 55 are formed as clock marks at the time ofmanufacturing. User data is recorded on the grooves and the lands otherthan concave portions 50 and convex portions 55.

As shown in FIG. 7, formatter 206 adds a non-recorded area (Reserve)between data blocks, a pre-write field immediately before each datablock, and a post-write field immediately after each data block. Thenonrecorded area (Reserve) corresponds to above described concaveportion 50 and convex portion 55.

In the second embodiment, data is divided into data blocks of aprescribed length after precoding of a constraint length L+1 (for L is anatural number) in precoder 202.

Prediction portion 207 performs a control operation to insert particularintrinsic patterns in pre-write and post-write fields. In this case, thefixed pattern length is at least L, and the relationship between apostwrite pattern length and a pre-write pattern length may notparticularly be limited but they may be the same or different.

Now, formatting by prediction portion 207 and formatter 206 in thesecond embodiment will be described by taking data blocks N and N+1 asan example. In the second embodiment, an intrinsic pattern starting witha pattern of successive repetition of the foremost data of data blockN+1 is inserted in a post-write field corresponding to data block N. Thenumber of repetition is at least L+1. In a pre-write field correspondingto data block N+1, an intrinsic pattern ending with the rearmost data ofdata block N is inserted.

In a PR (1, 1) method, for example, if the first data of data block N+1is “0,” then the front portion of an intrinsic pattern to be inserted ina post-write field corresponding to data block N is a pattern startingwith “0.” If the rearmost data of data block N is “0,” then the rearpattern of an intrinsic portion to be inserted in a pre-write fieldcorresponding to data block N+1 is a pattern ending with “0.”

In other words, prediction portion 207 designates an intrinsic pattern,which maintains code correlation at a block division location, accordingto preceding. Based on it, formatter 206 inserts an intrinsic patternbefore and after a data block. Therefore, without causing a decodingerror in maximum likelihood decoding in multi-value discriminationportion 603, it becomes possible to insert particular data in precodeddata.

An intrinsic pattern may be inserted not only before and after a datablock but before or after the data block according to the abovedescribed conversion rule.

Third Embodiment

In the above described first and second embodiments, the transmissioncoefficient H(D) of the transmission system for reproducing datarecorded on magneto-optical disk 3 provides waveform equalization inequalizer 602 to satisfy the expressions (1) and (2). The signaltransmission scheme represented by such a transmission coefficient H (D)is referred to as the PR (1, 1) method.

H(D)=1+D  (1)

D=e ^(jwT)  (2)

In the expressions (1) and (2), symbol T is a bit cycle, symbol w is afrequency, and symbol D is a delay operation element in bit cycle T.

On the other hand, the transmission coefficient H (D) of thetransmission system may provide waveform equalization in equalizer 602to satisfy the expressions (3) and (4).

H(D)=(1+D)²  (3)

D=e ^(jwT)  (2)

The signal transmission scheme represented by such a transmissioncoefficient H (D) is referred to as the PR (1, 2, 1) method. The thirdembodiment is directed to signal transmission of the PR (1, 2, 1)method. The data format is as described with respect to FIG. 3.

Now, formatting by prediction portion 207 and formatter 206 in the thirdembodiment will be described by taking data blocks N and N+1 as anexample. In the third embodiment, an intrinsic pattern determinedaccording to the last data D (511) included in data block N of datasegment N is inserted in a pre-write field corresponding to data blockN+1 (data segment N+1). This is performed for the purpose of maintainingcode correlation of the PR method similarly to the conversion ruledescribed with respect to the first embodiment.

On the other hand, in a post-write field corresponding to data block N(data segment N), an intrinsic pattern determined according to the lastdata D (511) included in data block N of data segment N is inserted.This is performed for the purpose of reliably preventing a decodingerror of maximum likelihood decoding by generating traceback on theboundary between a post-write field and a data block.

In maximum likelihood decoding in signal transmission of the PR method,the most possible one of paths led to each state at each time isselected as a “survived path.” If a particular pattern is input at thistime, the “survived path” and the state as a base are uniquelydetermined (merged). Since the path can be followed (traced back) fromthe uniquely determined state, a path found before the particularpattern is input can be determined. Therefore, when a particular patternis inserted before and after a data block, a path before insertion canbe uniquely determined.

In maximum likelihood decoding in signal transmission of the PR (1, 2,1) method, input of a signal “000” or “111” generates traceback. Thetraceback is generated at a post-write field portion. In order to do so,an intrinsic pattern to be inserted in a post-write field of datasegment N is determined according to the last data D (511) of datasegment N.

More specifically, as shown in FIGS. 8A and 8B, if intrinsic patternscorresponding to a pre-write field are “1100” and “0011” and the lastdata D (511) of data block N is “0,” then “1100” is recorded on thepre-write field corresponding to data block N+1. If the last data D(511) is “1,” then “0011” is recorded on the pre-write fieldcorresponding to data block N+1. Thus, code correlation of the PR methodis maintained.

If intrinsic patterns corresponding to a post-write field are “0011” and“1100” and the last data D (511) of data block N is “0,” then “0011” isrecorded on the post-write field corresponding to data block N. If thelast data D (511) is “1,” then “1100” is recorded on the post-writefield corresponding to data block N. Therefore, it becomes possible toprevent occurrence of a decoding error in maximum likelihood decoding,and complete maximum likelihood decoding for each data block bygeneration of traceback.

It is noted that an intrinsic pattern may be inserted not only beforeand after a data block but before or after the data block according tothe above described conversion rule.

Fourth Embodiment

The configuration shown in the second embodiment was provided as anextension of the first embodiment. Likewise, the structure of a fourthembodiment described below can be provided as an extension of the abovedescribed third embodiment. The conversion rule described in the thirdembodiment is applied to the stream of a data format in which precodeddata of a constraint length of L+1 (L is a natural number) is dividedinto data blocks of a prescribed length and a particular pattern isinserted between data blocks.

As described with respect to FIG. 7, formatter 206 adds a non-recordedarea (Reserve) between data blocks, a pre-write field immediately beforeeach data block, and a post-write field immediately after each datablock. Prediction portion 207 performs a control operation to insert aparticular intrinsic pattern in a pre-write field and a post-writefield.

Now, formatting by prediction portion 207 and formatter 206 in thefourth embodiment will be described by taking data blocks N and N+1 asan example. In the fourth embodiment, an intrinsic pattern determinedaccording to the rearmost data of data block N located immediatelybefore is inserted in a pre-write field corresponding to data block N+1.Thus, code correlation is maintained.

In a post-write field corresponding to data block N, such a pattern isinserted that has successive repetition of the rearmost data of datablock N. The number of repetition is at least L if the constraint lengthis L+1. Since traceback is generated on the boundary between thepost-write field and the data block as a result, a decoding error ofmaximum likelihood decoding can be prevented reliably.

A case of the PR (1, 2, 1) method will be described. Assume that thedata bit string representing data in a data block is D(0), . . . , D(J)(for J is a natural number). An intrinsic pattern to be inserted in thepre-write field corresponding to data block N+1 includes 2 bits formedof the last bit of data block N and a bit immediately before the lastbit (that is, D(J) and D(J−1)). Furthermore, an intrinsic pattern to beinserted in the post-write field corresponding to data block N includes2 bits formed of the last bit of data block N and a bit immediatelybefore the last bit (that is, D(J) and D(J−1)).

Therefore, even when precoded data is divided into blocks to insert andrecord an intrinsic pattern and the recorded data is read out to performwaveform equalization and maximum likelihood decoding, occurrence of adecoding error in maximum likelihood decoding at each data block end canbe prevented. When the rearmost data of a data block located immediatelybefore is added to the front portion of the following data block anddata which generates traceback at the rearmost portion of a data blockis added at the rearmost portion of the data block, maximum likelihooddecoding can be completed for each data block.

An intrinsic pattern may be inserted not only before and after a datablock but before or after the data block according to the abovedescribed conversion rule.

It should be understood that the embodiments disclosed herein areillustrative and not restrictive in any detail. It is to be noted thatthe scope of the present invention which is defined not by the abovedescription of the embodiments but by the claims covers allmodifications within the range equivalent to the claims.

What is claimed is:
 1. A recording device for recording data on arecording medium using a method in which data is reproduced by utilizinginter-symbol interference, comprising: a precoder for preceding inputdata to adjust to said recording medium; a formatter for dividing saidprecoded data into a plurality of data blocks and adding a correspondingintrinsic pattern to an end of each of said plurality of data blocks; apattern determination unit for determining said corresponding intrinsicpattern for the end of each of said plurality of data blocks; and arecord unit for recording an output of said formatter on said recordingmedium, wherein said pattern determination unit determines saidcorresponding intrinsic pattern to reduce a decoding error of data atthe end of each of said plurality of data blocks, and wherein saidpattern determination unit selects, as said corresponding intrinsicpattern, one of predetermined at least two intrinsic patterns for eachof said plurality of data blocks.
 2. The recording device according toclaim 1, wherein said corresponding intrinsic pattern is formed of suchdata among data included in a data block adjacent to a correspondingdata block that is adjacent to an end of said corresponding data blockbefore division into said blocks.
 3. The recording device according toclaim 1, wherein said corresponding intrinsic pattern is combined withdata at an end of a corresponding data block to generate traceback. 4.The recording device according to claim 3 wherein the end of each ofsaid plurality of data blocks is a rear end of each of said plurality ofdata blocks, and foremost data of said corresponding intrinsic patternis identical to rearmost data of said corresponding data block.
 5. Therecording device according to claim 3, wherein the end of each of saidplurality of data blocks is a rear end of each of said plurality of datablocks, and said corresponding intrinsic pattern is “1100” when rearmostdata of said corresponding data block is “1,” and “0011” when rearmostdata of said corresponding data block is “0.”
 6. The recording deviceaccording to claim 3, wherein the end of each of said plurality of datablocks is a rear end of said plurality of data blocks, and foremost dataof said corresponding intrinsic pattern has at least two repetition ofrearmost data of said corresponding data block.
 7. The recording deviceaccording to claim 1, wherein the end of each of said plurality of datablocks is a front end of each of said plurality of data blocks, and saidpattern determination unit determines said corresponding intrinsicpattern according to rearmost data of a data block located immediatelybefore a corresponding data block.
 8. The recording device according toclaims 7, wherein said corresponding intrinsic pattern is “0011” whenthe rearmost data of the data block located immediately before saidcorresponding data block is “1,” and “1100” when the rearmost data ofthe data block located immediately before said corresponding data blockis “0.”
 9. The recording device according to claim 1, wherein the end ofeach of said plurality of data blocks is a rear end of each of saidplurality of data blocks, and said pattern determination unit determinessaid corresponding intrinsic pattern according to foremost data of adata block located immediately after a corresponding data block.
 10. Therecording device according to claim 9, wherein said correspondingintrinsic pattern is “1100” when the foremost data of the data blockimmediately after said corresponding data block is “1,” and “0011” whenthe foremost data of the data block immediately after said correspondingdata block is “0.”
 11. The recording device according to claim 1,wherein said pattern determination unit selects one of a first patternand a second pattern which is an inversion of said first pattern. 12.The recording device according to claim 1, wherein the reproductionmethod utilizing said inter-symbol interference is a PR (1, 1) method.13. The recording device according to claim 1, wherein the reproductionmethod utilizing said inter-symbol interference is a PR (1, 2, 1)method.
 14. The recording device according to claim 1, whereinprescribed information is previously recorded as a physical form on saidrecording medium, and said formatter performs division into said blocksto allow said precoded data to be recorded on a recording area otherthan that of said physical form in said recording medium.
 15. Arecording device for recording data on a recording medium using a methodin which data is reproduced by utilizing inter-symbol interference,comprising: a precoder for preceding input data to adjust to saidrecording medium; a formatter for dividing said precoded data into aplurality of data blocks and adding a corresponding intrinsic pattern toan end of each of said plurality of data blocks; a pattern determinationunit for determining said corresponding intrinsic pattern for the end ofeach of said plurality of data blocks; and a record unit for recordingan output of said formatter on said recording medium, wherein saidpattern determination unit determines said corresponding intrinsicpattern to reduce a decoding error of data at the end of each of saidplurality of data blocks, and wherein said corresponding intrinsicpattern is formed of such data among data included in a data blockadjacent to a corresponding data block that is adjacent to an end ofsaid corresponding data block before division into said blocks.
 16. Therecording device according to claim 15, wherein said correspondingintrinsic pattern is combined with data at an end of a correspondingdata block to generate traceback.
 17. The recording device according toclaim 16, wherein the end of each of said plurality of data blocks is arear end of each of said plurality of data blocks, and foremost data ofsaid corresponding intrinsic pattern is identical to rearmost data ofsaid corresponding data block.
 18. The recording device according toclaim 16, wherein the end of each of said plurality of data blocks is arear end of each of said plurality of data blocks, and saidcorresponding intrinsic pattern is “1100” when rearmost data of saidcorresponding data block is “1,” and “0011” when rearmost data of saidcorresponding data block is “0.”
 19. The recording device according toclaim 16, wherein the end of each of said plurality of data blocks is arear end of each of said plurality of data blocks, and foremost data ofsaid corresponding intrinsic pattern has at least two repetition ofrearmost data of said corresponding data block.
 20. The recording deviceaccording to claim 15, wherein the end of each of said plurality of datablocks is a front end of each of said plurality of data blocks, and saidpattern determination unit determines said corresponding intrinsicpattern according to rearmost data of a data block located immediatelybefore a corresponding data block.
 21. The recording device according toclaim 20, wherein said corresponding intrinsic pattern is “0011” whenthe rearmost data of the data block located immediately before saidcorresponding data block is “1,” and “1100” when the rearmost data ofthe data block located immediately before said corresponding data blockis “0.”
 22. The recording device according to 15, wherein the end ofeach of said plurality of data blocks is a rear end of each of saidplurality of data blocks, and said pattern determination unit determinessaid corresponding intrinsic pattern according to foremost data of adata block located immediately after a corresponding data block.
 23. Therecording device according to claim 22, wherein said correspondingintrinsic pattern is “1100” when the foremost data of the data blockimmediately after said corresponding data block is “1,” and “0011” whenthe foremost data of the data block immediately after said correspondingdata block is “0.”
 24. The recording device according to claim 15,wherein said pattern determination unit sets as said correspondingintrinsic pattern one of a first pattern and a second pattern which isan inversion of said first pattern.
 25. The recording device accordingto claim 15, wherein the reproduction method utilizing said inter-symbolinterference is a PR (1, 1) method.
 26. The recording device accordingto claim 15, wherein the reproduction method utilizing said inter-symbolinterference is a PR (1, 2, 1) method.
 27. The recording deviceaccording to claim 15, wherein prescribed information is previouslyrecorded as a physical form on said recording medium, and said formatterperforms division into said blocks to allow said precoded data to berecorded on a recording area other than that of said physical form insaid recording medium.
 28. A recording device for recording data on arecording medium of a method in which data is reproduced by utilizinginter-symbol interference, comprising: a precoder for precoding inputdata to adjust to said recording medium, a formatter for dividing saidprecoded data into a plurality of data blocks and adding a correspondingfirst intrinsic pattern to a front end of each of said plurality of datablocks and a corresponding second intrinsic pattern to a rear end ofeach of said plurality of data blocks; a pattern determination unit fordetermining said corresponding first intrinsic pattern and saidcorresponding second intrinsic pattern for each of said plurality ofdata blocks; and a record unit for recording an output of said formatmeans on said recording medium, wherein said pattern determination unitdetermines said corresponding first intrinsic pattern according torearmost data of a data block located immediately before a correspondingdata block, and determines said corresponding second intrinsic patternaccording to rearmost data of said corresponding data block.
 29. Therecording device according to claim 28, wherein said correspondingsecond intrinsic pattern is combined with the rearmost data of saidcorresponding data block to generate traceback.
 30. The recording deviceaccording to claim 29, wherein foremost data of said correspondingsecond intrinsic pattern is identical to the rearmost data of saidcorresponding data block.
 31. The recording device according to claim28, wherein rearmost data of said corresponding first intrinsic patternis identical to the rearmost data of the data block located immediatelybefore said corresponding data block.
 32. The recording device accordingto claim 28, wherein foremost data of said corresponding secondintrinsic pattern has at least two repetition of the rearmost data ofsaid corresponding data block.
 33. The recording device according toclaim 29, wherein foremost data of said corresponding second intrinsicpattern has at least two repetition of the rearmost data of saidcorresponding data block.
 34. The recording device according to claim28, wherein the reproduction method utilizing said inter-symbolinterference is a PR (1, 1) method.
 35. The recording device accordingto claim 29, wherein the reproduction method utilizing said inter-symbolinterference is a PR (1, 1) method.
 36. The recording device accordingto claim 28, wherein the reproduction method utilizing said inter-symbolinterference is a PR (1, 2, 1) method.
 37. The recording deviceaccording to claim 29, wherein the reproduction method utilizing saidinter-symbol interference is a PR (1, 2, 1) method.
 38. The recordingdevice according to claim 28, wherein said corresponding secondintrinsic pattern is “1100” when the rearmost data of said correspondingdata block is “1,” and “0011” when the rearmost data of saidcorresponding data block is “0.”
 39. The recording device according toclaim 29, wherein said corresponding second intrinsic pattern is “1100”when the rearmost data of said corresponding data block is “1,” and“0011” when the rearmost data of said corresponding data block is “0.”40. The recording device according to claim 28, wherein saidcorresponding first intrinsic pattern is “0011” when the rearmost dataof the data block located immediately before said corresponding datablock is “1,” and “1100” when the rearmost data of the data blocklocated immediately before said corresponding data block is “0.”
 41. Therecording device according to claim 31, wherein said corresponding firstintrinsic pattern is “0011” when the rearmost data of the data blocklocated immediately before said corresponding data block is “1,” and“1100” when the rearmost data of the data block located immediatelybefore said corresponding data block is “0.”
 42. The recording deviceaccording to claim 28, wherein said pattern determination unit sets assaid corresponding first intrinsic pattern one of a first pattern and asecond pattern which is an,Aversion of said first pattern, and sets assaid corresponding second intrinsic pattern one of a first pattern and asecond pattern which is an inversion of said first pattern.
 43. Therecording device according to claim 29, wherein said patterndetermination unit sets as said corresponding first intrinsic patternone of a first pattern and a second pattern which is an inversion ofsaid first pattern, and sets as said corresponding second intrinsicpattern one of a first pattern and a second pattern which is aninversion of said first pattern.
 44. The recording device according toclaim 28, wherein prescribed information is previously recorded as aphysical form on said recording medium, and said formatter performsdivision into said blocks to allow said precoded data to be recorded ona recording area other than that of sail physical form in said recordingmedium.
 45. The recording device according to claim 29, whereinprescribed information is previously recorded as a physical form on saidrecording medium, and said formatter performs division into said blocksto allow said precoded data to be recorded on a recording area otherthan that of said physical form in said recording medium.